Piston for expansion-engines.



R. S. MOORE.

PISTON FOR EXPANSION ENGINES.

APPLICATION FILED 1AN.5. 1912.

1,159,066. Patented Nov. 2, 1915.

2 SHEETS-SHEET l- El vwwtoz R. S. MOORE.

PISTON FOR EXPANSION ENGINES.

APPLICATION FILED JAN.5. I912.

Patented Nov. 2, 1915.

2 SHEETS-SHEET 2.

III l 7 I]? 5 I2 I? UNITED STATES 'PATE' roFFioE.

ROBERT S. MOORE, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO-GYRO IMOTOR COMPANY, OF WASHINGTON, DISTRICT OF COLUMBIA, A CORPORATION OFDELAWARE.

To all whom it ma concern:

Be it known that I, ROBERT S. MooRE, a citizen of the United States,residing at Washington, in the District of Columbia, have inventedcertain new and useful Improvements in Pistons for Expansion-Engines, ofwhich the following is a description, reference being had to theaccompanying drawing, and to the lettersand figures of reference markedthereon.

The invention relates to new, and useful improvements in pistons ingeneral, and more especially to pistons for use in connection withexpansion engines, such as gas engines.

An object of the invention is to provide a piston with a device forproducing a smooth sliding fit between the piston and the cylinder,which is not liable to cause the piston to bind in the cylinder, orcause undue wear or scoring of the surface of the cylinder by reason ofthe expansion of the metal in the head of the piston, due to the heat ofthe expanding gases.

A further object of the invention is to provide a piston with a metalring which is located adjacent the head of the piston, and soconstructed that the expanding of the gases will cause the ring toexpand and engage the wall of the cylinder, thereby providing a perfectjoint between the piston head and the wall of the cylinder. v

These and other objects will in part be obvious and will in part behereinafter more fully described. In the drawings which show by way ofillustration one embodiment of -the invention z-Figure 1 is a sectionalview through a piston head, having my improvements applied thereto, andshowing the relation of the same tothe wall of the cylinder; Fig. 2 isan edge view of the expansible ring with a part thereof broken away insection to show the construction of the ring; Fig. 3'is a similar viewshowing the manner in which the ring may be expanded; Fig. 4 is a viewsimilar to Fig. 1, showing a modified form of construction of the ringand the seat therefor Fig. 5 is a viewsimilar to Fig. 2, of the form ofring shown in Fig. 4; Fig. 6 is a view similar to Fig. 1 showing a stillfurther modification of the ring for forming a tight joint between thepiston and the wall of the cylinder; Fig-7 is an enlarged view showingthe -Specification of Letters Patent. Application filed January 5, 1912.Seri aI No. 669,576.

PISTON FOR EXPANSION -ENGIN ES.

Patented Nov. 2, 1915.

manner in which the ring may tilt; Fig. 8 1s a plan .view of the ringshown in Fig. 6.

In the drawings, I have shown in section the wall of a cylinder 1, whichis provided with a plurality of heat radiating ribs. Located within thecylinder, is a piston 2. The piston as herein shown, is provided with arelatively thin head 3, and acylindrical wall or body portion 4, whichengages the inner surface of the cylinder. Said piston head is formedwith an opening 5 adapted to receive the valve seat so that the intakemay be through the center of the piston. It is obvious however, thatthis construction of the head forms no part of the present invention,and other forms of piston heads may be used.

The piston is formed with an annular groove 6 which is located adjacentthe outer face of the head, and in the outer wall of the cylindricalportion 4 of the piston. Located within the annular groove 6 is a ring7. This ring 7 is preferably made of cast iron, and is split as at 8, sothat the ring may expand slightly under pressure, as shown in Fig. 3.The ring is angular in shape, thus providing a flange 9 which seats inthe annular groove, and a projecting rim 10, which extends forwardly,that is, into the expansion chamber. 1

The inner wall 11 adjacent its forward end is chamfered or inclined sothat the extreme edge of the ring is brought to a comparatively sharpedge. This ring 7 rests freely in' the annular groove 6, and will becaused through the connection between the flange 9 and the walls of thegroove, to move with the piston as reciprocates in the cylinder.

In the operation of the device, the expan sion of the gases in thecombustion chamber will exert a pressure against the inner wall of thering 7 and thereby cause the ring to expand, which expansion ispermitted owing to' the ring being split, and the outer wall of the ringto make a firm eontact'with the wall of the cylinder. The expansion ofthegroove, and about the piston. By this construction, the piston may beturned so as to have a very free movement in the cylinder, and anyexpansion of the piston will not 7, which seats against the wall 14;, issimi-,

cause a binding of the piston in the-cylinder, or a scoring of the wallof the cylinder. While thepiston moves freely in the cylinder, theexpansible ring will make aperfect contact with the wall of thecylinder, and

prevent any leakage of the expanding gases about-the piston.

In Fig. 4, I have shown a piston 2 wherein the annular groove 12 for theexpansible ring 13 is formed so that the Wall llis inclined backwardl'yand the wall of the ring larly inclined. By this construction, theexpanding gases in the combustion chamber, not only forces the ringoutwardly against the-wall of the cylinder, but by forcing the'ringagainst its seat, the inclined walls are caused to contact and toslide one on the other, thus further forcing the expansible ring outwardtoward the wall of the cylinder. v I I The operation of the piston, asshown in Figs. 4 and. 5, is precisely the same as in Figs. 1 to 3inclusive, except that the inclined wall increases the effective forcingof the ring against the wall of the cylinder.

.In Figs. 6 to 8 inclusive, I have shown the expansiblering 15 as madein four sections. The flange 16 projecting inwardly toward the center ofthe piston head, is also longer.

The upper wall 17 of the annular groove 18 gal force acting upon thering, will cause the sections of the ring to swing about the fulcrumpoint 19, and the outer edge 20 to be brought in contact with the wallof the cylinder, as shown in Fig. 6.

By forming the ring in sections, each section may swing or tilt aboutthe fulcrum edge 19, in the manner above described. While I have shownthe ring made in four sections, it is obvious that said ring may beotherwise divided, and may be made in two sections, three sections, orany other number of sections. Not only will the sections of the Thisful;

ring be caused through centrifugal force toproperly engage the wall ofthe cylinder,

' details of construction, as described, may be made without departingfrom the spirit of the invention as set forth in the appended C aims.

Having thusparticularly described my invention, what I claim as new anddesire to secure by Letters Patent, is

1. A piston comprising a body portion having an annular groove in theside face thereof adjacent the head, and a-single split ring having aninwardly projecting retaining flange substantially fitting said groove,

and an integral annular projection extending toward the outer face ofthe'piston head, the inner wall of said annular projection beinginclined relative to the .outer wall thereof so as to formasubstantially sharp outer edge, said flange being adapted to freelyseat in the annular groove, whereby the expansion of the gases in thecombustion cham; ber will cause said ring to expand and the outer wallthereof to contact with the wall of the cylinder.

2. A piston comprising a body portion having an inclined annular groovein the side face thereof adjacent the head, an expansible ring having aninwardly projecting flange loosely fitting said groove, and an annularprojectionextending toward the outer face of the piston head, wherebythe expanding ofthe. gases in the combustion chamber forcing the ringagainst its seat will force the outer surface of the ringagainst thewall of the cylinder and cause the upper and lower faces of the flangeto firmly engage the upper and lower walls of the groove.

In testimony whereof I affixmy signature.

in presence of two witnesses.

ROBERT S. MOORE, Witnesses:

A. M. PARKINS, v C. L. STUBTEVANT.

